A video encoder compresses a video signal so that either more information can be sent over a given available bandwidth for transmission or a much smaller compressed file results for storage. Alternatively, an improved video encoder may choose to provide either even higher compression or even better quality for the same given available bandwidth or file size. The transmitted compressed video signal or stored compressed file may be input to a video receiver/decoder for decoding and playback for display. For example, the High Efficiency Video Coding (HEVC)/H.265 video coding standard is a state-of-the-art standard that provides for high video compression/quality while requiring much lower bandwidth or generating much smaller compressed file sizes for the same quality as compared to earlier standards. HEVC is thus a significant candidate for replacing earlier standards. However HEVC only focuses on the compression and decompression of progressive scan video. For instance, in progressive scan video, all of each frame is captured and displayed at an instant of time in contrast to interlaced video in which each frame is composed of a pair of fields that are captured or displayed from two subsequent intervals of time. Thus, the interlaced scan video where each frame is composed of two fields as captured by a camera or when intended for display, nearly doubles the perceived amount of motion that can be captured or the temporal rate of motion (allows smooth motion rendition) that can be displayed, as is discussed further herein.
Ideally, even better rendition of motion can be obtained by capturing the progressive format video at twice the frame rate, outperforming the motion rendition capability of the interlaced format, however, this also results in excessive increase in bandwidth. Thus, the interlaced format may provide a more balanced motion rendition capability/bandwidth increase tradeoff. However in case of slower motion of objects in a video scene, interlaced video format can also provide increased visual degradation, especially on objects with sharp edges including the case of text. Due to such visual degradation, there has been a movement away from the interlaced format to the progressive format. Further, due to perception of potentially lower visual distortions, the display technology has also evolved towards display of progressive video format as the de-facto format for display. Thus, recent coding standards such as HEVC only focus on coding of progressive format video (although HEVC includes bits for signaling interlaced format video, it does not support additional tools for interlaced format compression) expecting video of progressive format input to the HEVC encoder and the output video of the HEVC decoder to be progressive format for presentment via a progressive format display.
Typical conversions to a suitable format for compression may be difficult and may provide a variety of undesirable conversion artifacts. As such, existing techniques do not provide high quality conversion of source video to a format suitable for compression using state-of-the art video codecs. Such problems may become critical as the desire to deliver high quality consumer grade video via digital standard definition, high definition, and ultra-high definition becomes more widespread.